1. Field of the Invention
This invention relates to the production of novel amphoteric surface active agents formed from novel tertiary amides and thermodynamically and kinetically controlled processes for the manufacture of each of these. The tertiary amides of this invention are therefore useful intermediates in the production of the present amphoteric surfactants, which themselves are useful for a variety of purposes including, e.g., the manufacture of improved shampoos, wetting agents, anti-static agents, detergents, emulsifiers, hard surface cleaners, lubricants, etc. The tertiary amides of the invention are derived by condensation of esters of fatty acids with aminoalkyl alkanolamines and generally are characterized by the formula: ##EQU1## wherein: R.sub.1 is a hydrocarbon radical having from five to twenty-nine carbon atoms, and, when substituted, contains such typical substituents as Cl; Br; OH; or OAlkyl such as OCH.sub.3 ; and
R.sub.2, r.sub.3, r.sub.4 and R.sub.5 are each hydrogen or unsubstituted or substituted aliphatic hydrocarbon radicals having from one to four carbon atoms which, when substituted, have the same substituents as defined in R.sub.1 above.
2. Description of the Prior Art
The production of amphoteric surfactants by reacting fatty amides of hydroxy diamines such as aminoalkyl alkanolamine with monohalocarboxylic acids is disclosed, for example, in U.S. Pat. Nos. 2,961,541 and 2,970,160. However, the amides there disclosed are secondary amides as are those typically prepared by condensation of a fatty acid with an aminoalkyl alkanolamine, such as is disclosed in U.S. Pat. No. 2,344,260. This latter reaction is normally carried out in the range of 130.degree. to 200.degree. C, and even after a prolonged period of heating gives conversions only on the order of 60 to 75%, unlike those of the present invention wherein conversions of 90% or higher are achieved.
Heretofore, amphoteric surface active agents of improved characteristics have not been made from tertiary amides, in large part because amide surfactants have conventionally been prepared from secondary amides. The present invention now is able to fill these voids and permit the production of superior surface active agents.
It is therefore a primary object of this invention to provide useful amphoteric surfactants containing tertiary amide groups for example by condensation of novel tertiary amides with a monohalocarboxylic acid or suitable salt thereof. Such surfactants, because of their unique structural features, offer properties which lend themselves to new and improved surfactant compositions useful, for example, in a number of ways as indicated above.